![Alex Elder](/assets/img/avatar_default.png)
This is an old patch that I neglected to send out. It's cleaning up a couple things that got committed before I had a chance to comment on them. In operation.c there is a "FIXME" comment that is easily proven wrong by inspection. In gb_protocol_put(), there is another wrong "FIXME" comment as well. We can also use our cached copies of the protocol major and minor version number in another spot. And balance that out by using a cached copy of the protocol id. Signed-off-by: Alex Elder <elder@linaro.org> Reviewed-by: Johan Hovold <johan@hovoldconsulting.com> Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
221 lines
5 KiB
C
221 lines
5 KiB
C
/*
|
|
* Greybus protocol handling
|
|
*
|
|
* Copyright 2014-2015 Google Inc.
|
|
* Copyright 2014-2015 Linaro Ltd.
|
|
*
|
|
* Released under the GPLv2 only.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include "greybus.h"
|
|
|
|
/* Global list of registered protocols */
|
|
static DEFINE_SPINLOCK(gb_protocols_lock);
|
|
static LIST_HEAD(gb_protocols);
|
|
|
|
/* Caller must hold gb_protocols_lock */
|
|
static struct gb_protocol *_gb_protocol_find(u8 id, u8 major, u8 minor)
|
|
{
|
|
struct gb_protocol *protocol;
|
|
|
|
list_for_each_entry(protocol, &gb_protocols, links) {
|
|
if (protocol->id < id)
|
|
continue;
|
|
if (protocol->id > id)
|
|
break;
|
|
|
|
if (protocol->major > major)
|
|
continue;
|
|
if (protocol->major < major)
|
|
break;
|
|
|
|
if (protocol->minor > minor)
|
|
continue;
|
|
if (protocol->minor < minor)
|
|
break;
|
|
|
|
return protocol;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
int __gb_protocol_register(struct gb_protocol *protocol, struct module *module)
|
|
{
|
|
struct gb_protocol *existing;
|
|
u8 id = protocol->id;
|
|
u8 major = protocol->major;
|
|
u8 minor = protocol->minor;
|
|
|
|
protocol->owner = module;
|
|
|
|
/*
|
|
* The protocols list is sorted first by protocol id (low to
|
|
* high), then by major version (high to low), and finally
|
|
* by minor version (high to low). Searching only by
|
|
* protocol id will produce the newest implemented version
|
|
* of the protocol.
|
|
*/
|
|
spin_lock_irq(&gb_protocols_lock);
|
|
|
|
list_for_each_entry(existing, &gb_protocols, links) {
|
|
if (existing->id < id)
|
|
continue;
|
|
if (existing->id > id)
|
|
break;
|
|
|
|
if (existing->major > major)
|
|
continue;
|
|
if (existing->major < major)
|
|
break;
|
|
|
|
if (existing->minor > minor)
|
|
continue;
|
|
if (existing->minor < minor)
|
|
break;
|
|
|
|
/* A matching protocol has already been registered */
|
|
spin_unlock_irq(&gb_protocols_lock);
|
|
|
|
return -EEXIST;
|
|
}
|
|
|
|
/*
|
|
* We need to insert the protocol here, before the existing one
|
|
* (or before the head if we searched the whole list)
|
|
*/
|
|
list_add_tail(&protocol->links, &existing->links);
|
|
spin_unlock_irq(&gb_protocols_lock);
|
|
|
|
pr_info("Registered %s protocol.\n", protocol->name);
|
|
|
|
/*
|
|
* Go try to bind any unbound connections, as we have a
|
|
* new protocol in the system
|
|
*/
|
|
gb_bundle_bind_protocols();
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__gb_protocol_register);
|
|
|
|
/*
|
|
* De-register a previously registered protocol.
|
|
*
|
|
* XXX Currently this fails (and reports an error to the caller) if
|
|
* XXX the protocol is currently in use. We may want to forcefully
|
|
* XXX kill off a protocol and all its active users at some point.
|
|
* XXX But I think that's better handled by quiescing modules that
|
|
* XXX have users and having those users drop their reference.
|
|
*
|
|
* Returns true if successful, false otherwise.
|
|
*/
|
|
int gb_protocol_deregister(struct gb_protocol *protocol)
|
|
{
|
|
u8 protocol_count = 0;
|
|
|
|
if (!protocol)
|
|
return 0;
|
|
|
|
spin_lock_irq(&gb_protocols_lock);
|
|
protocol = _gb_protocol_find(protocol->id, protocol->major,
|
|
protocol->minor);
|
|
if (protocol) {
|
|
protocol_count = protocol->count;
|
|
if (!protocol_count)
|
|
list_del(&protocol->links);
|
|
}
|
|
spin_unlock_irq(&gb_protocols_lock);
|
|
|
|
if (protocol)
|
|
pr_info("Deregistered %s protocol.\n", protocol->name);
|
|
|
|
return protocol && !protocol_count;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gb_protocol_deregister);
|
|
|
|
/* Returns the requested protocol if available, or a null pointer */
|
|
struct gb_protocol *gb_protocol_get(u8 id, u8 major, u8 minor)
|
|
{
|
|
struct gb_protocol *protocol;
|
|
u8 protocol_count;
|
|
|
|
spin_lock_irq(&gb_protocols_lock);
|
|
protocol = _gb_protocol_find(id, major, minor);
|
|
if (protocol) {
|
|
if (!try_module_get(protocol->owner)) {
|
|
protocol = NULL;
|
|
} else {
|
|
protocol_count = protocol->count;
|
|
if (protocol_count != U8_MAX)
|
|
protocol->count++;
|
|
}
|
|
}
|
|
spin_unlock_irq(&gb_protocols_lock);
|
|
|
|
if (protocol)
|
|
WARN_ON(protocol_count == U8_MAX);
|
|
else
|
|
pr_err("protocol id %hhu version %hhu.%hhu not found\n",
|
|
id, major, minor);
|
|
|
|
return protocol;
|
|
}
|
|
|
|
int gb_protocol_get_version(struct gb_connection *connection, int type,
|
|
void *request, int request_size,
|
|
struct gb_protocol_version_response *response,
|
|
__u8 major)
|
|
{
|
|
int retval;
|
|
|
|
retval = gb_operation_sync(connection, type, request, request_size,
|
|
response, sizeof(*response));
|
|
if (retval)
|
|
return retval;
|
|
|
|
if (response->major > major) {
|
|
dev_err(&connection->dev,
|
|
"unsupported major version (%hhu > %hhu)\n",
|
|
response->major, major);
|
|
return -ENOTSUPP;
|
|
}
|
|
|
|
dev_dbg(&connection->dev, "version_major = %u version_minor = %u\n",
|
|
response->major, response->minor);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gb_protocol_get_version);
|
|
|
|
void gb_protocol_put(struct gb_protocol *protocol)
|
|
{
|
|
u8 id;
|
|
u8 major;
|
|
u8 minor;
|
|
u8 protocol_count;
|
|
|
|
if (!protocol)
|
|
return;
|
|
|
|
id = protocol->id;
|
|
major = protocol->major;
|
|
minor = protocol->minor;
|
|
|
|
spin_lock_irq(&gb_protocols_lock);
|
|
protocol = _gb_protocol_find(id, major, minor);
|
|
if (protocol) {
|
|
protocol_count = protocol->count;
|
|
if (protocol_count)
|
|
protocol->count--;
|
|
module_put(protocol->owner);
|
|
}
|
|
spin_unlock_irq(&gb_protocols_lock);
|
|
if (protocol)
|
|
WARN_ON(!protocol_count);
|
|
else
|
|
pr_err("protocol id %hhu version %hhu.%hhu not found\n",
|
|
id, major, minor);
|
|
}
|